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OBJECTIVE: To demonstrate directly that highly reactive hydroxyl radicals (OH.) can be generated in patients with rheumatoid arthritis and contribute to joint damage, and to examine the ability of blood to cause OH. generation. METHODS: The sensitive and specific technique of hydroxylation of aromatic compounds (salicylate and phenylalanine) was used to measure OH.. Synovial fluid and blood from patients with active rheumatoid arthritis were aspirated and immediately added to tubes containing salicylate and phenylalanine as detectors of OH., or to tubes containing saline as a control. Levels of specific products of attack of OH. upon salicylate (2,3- and 2,5-dihydroxybenzoates) and phenylalanine (ortho- and meta-tyrosines) were measured by high performance liquid chromatography. RESULTS: Synovial fluid samples aspirated into saline never contained ortho- or meta-tyrosines or 2,3-dihydroxybenzoate. Of 53 patients examined, synovial fluid and blood from 36 caused formation of ortho- and meta-tyrosines when aspirated into solutions containing phenylalanine. Repeated sampling from three "positive" patients showed consistent evidence of these hydroxylation products. Similarly, of 22 patients examined, synovial fluid and blood from 18 caused formation of 2,3- and 2,5-dihydroxybenzoates when aspirated into salicylate solutions. Further evidence for the role of OH. was provided by inhibition of the hydroxylation by the specific OH. scavengers mannitol and sodium formate. CONCLUSIONS: Aspirated knee joint fluids and blood from rheumatoid arthritis patients can generate OH., consistent with current views on the importance of this radical as a cytotoxic agent in rheumatoid disease. The ability of body fluids to cause OH. formation is not correlated with simple laboratory indices of disease activity, but is reproducible on sequential sampling from the same patients. The mechanism and significance of the phenomenon in rheumatoid arthritis pathology remain to be established.
Mixtures of Cu2+ and H2O2 at pH 7.4 caused damage to the bases in DNA greater than that caused by mixtures of Fe3+ and H2O2. Addition of ascorbic acid to the Cu2+/H2O2 system caused a very large increase in base damage, much greater than that produced by the Fe3+/H2O2/ascorbic acid system. The products of base damage in the presence of Cu2+ were typical products that have been shown to result from attack of hydroxyl radicals upon the DNA bases. Cytosine glycol, thymine glycol, 8-hydroxyadenine and especially 8-hydroxyguanine were the major products in both the Cu2+/H2O2 and the Cu2+/H2O2/ascorbic acid systems. Base damage in DNA by these systems was inhibited by the chelating agents EDTA and nitrilotriacetic acid and by catalase, but not by superoxide dismutase, nor by the hydroxyl-radical scavenger mannitol. It is proposed that Cu2+ ions bound to the DNA react with H2O2 and ascorbic acid to generate hydroxyl radicals, which then immediately attack the DNA bases in a site-specific manner. A hypoxanthine/xanthine oxidase system also caused damage to the DNA bases in the presence of Cu2+ ions. This was inhibited by superoxide dismutase and catalase. The high activity of Cu2+ ions, when compared with Fe3- ions, in causing hydroxyl-radical-dependent damage to DNA and to other biomolecules, means that the availability of Cu2+ ions in vivo must be carefully controlled.
Correspondence| August 01 1982 Superoxide-dependent formation of hydroxyl radicals in the presence of iron salts is a feasible source of hydroxy radicals in vivo B Halliwell B Halliwell Search for other works by this author on: This Site PubMed Google Scholar Biochem J (1982) 205 (2): 461–463. https://doi.org/10.1042/bj2050461 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn Email Cite Icon Cite Get Permissions Citation B Halliwell; Superoxide-dependent formation of hydroxyl radicals in the presence of iron salts is a feasible source of hydroxy radicals in vivo. Biochem J 1 August 1982; 205 (2): 461–463. doi: https://doi.org/10.1042/bj2050461 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Journal Search Advanced Search This content is only available as a PDF. © 1982 London: The Biochemical Society1982 Article PDF first page preview Close Modal You do not currently have access to this content.
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Reactive Oxygen and Oxidative Stress: A New Route for Tackling Disease? Scrip Report, anonymous, 1994 PJP Publications, UK.Non-Steroidal Anti-inflammatory Drugs: Mechanism and Clinical Uses Edited by Alan J. Lewis and Daniel E. Furst (Second edition) xii + 461 pages Marcel Dekker: New York, 1994 ISBN 0 8247–8856–7Bioinorganic Chemistry: An Inorganic Perspective of Life Edited by Dimitris P. Kessissoglou NATO AS1 (Advanced Science Institutes), Series C: Mathematical and Physical Sciences Volume 459:1995 Kluwer Academic Publishers: Dordrecht ISBN 0 7923 3380 2 xx + 415 pagesRegulatory Toxicology Edited by C.P. Chengelis, J.F. Holson and S.C. Gad Raven Press: New York, 1995, pp. ix + 251 ISBN 0 781 701 910, $109.50Oxidative Stress and Aging Edited by R.G. Cutler; L. Packer, J. Bertram and A. Mori Birkhauser Verlag AG, 1995 ISBN 3–7643–5039–3. £79, $124Neurotoxicology: Approaches and Methods Edited by L.W. Chang and W. Slikker Jr. Academic Press, San Diego ISBN 0–12–16 8055–X. $149.95 (£100 approx.)Radical Chemistry by M.J. Perkins Ellis Horwood Series in Organic Chemistry, Ellis Horwood Limited 1994 pp. 182 ISBN 013 3209202.King's College London Immunopharmacology of Free Radical Species Edited by D. Blake and P.G. Winyard Academic Press, London, pp. 301 ISBN 0121035204. £45.00.
Dehydroascorbate reductase was detected in the leaves of several plants and has been partially purified from spinach leaves. The enzyme has a MW of ca 25 000, a pH optimum of 7.5, a K m for glutathione (GSH) of 4.43 ± 0.4 mM and a Km for dehydroascorbate of 0.34 ± 0.05 mM. High concentrations of dehydroascorbate inhibit the enzyme. Cysteine cannot replace GSH as a donor. The purified dehydroascorbate reductase is extremely unstable and also inhibited by compounds which react with thiol groups. Dehydroascorbate does not protect the enzyme against such inhibition. GSH reduces dehydroascorbate non-enzymically at alkaline pH values.
Oxidative damage to DNA has been measured by quantitating 8-hydroxy-2′-deoxyguanosine (8-OHdGuo) after enzymic digestion of DNA, followed by HPLC separation and electrochemical detection. Alternatively, 8-hydroxyguanine (and a wide range of other base-derived products of free radical attack) may be measured after acidic hydrolysis of DNA or chromatin, followed by derivatization and gas-chromatography/mass spectrometry. Both techniques have comparable sensitivity, but GC/MS enables determination of a wide variety of chemical changes to all four DNA bases and it can be applied to DNA-protein complexes. However, the two techniques do not always give similar results. Potential reasons for this are discussed. Greater attention to methodological questions is required before using measurement of 8-OHdGuo as a "routine" marker of oxidative DNA damage in vivo.
